Hand Spinning vs. CNC Spinning: Two Sides of the Coin

Posted by Samuel Ibrahim, Jr. on Fri, Mar 14, 2014


describe the imageMetal Spinning (or spin forming) is a process where a tube or a disc of metal is rotated at high speed and transformed into an axially symmetrical object. Metal spinning is usually performed on a vertical or horizontal lathe using CNC controls or hand processing. So, by its very nature, metal spinning is an example of a technology that has spanned a timeframe stretching from the days of hand-tooled craftwork to the modern computer era. How do the two techniques compare, and how do they complement one another? Good questions. Let’s take a look.

During hand spinning, the operator controls both the spinning speed and forming forces. Hand spinning is a craft where the operator subtly works with the material to create a form. This is done through precise motions rather than brute force. A form is created by an operator who can feel the structure of the metal, its grain, its hardness, and its willingness to move in one direction or another. With one hand, the operator uses the spoon to shape the work piece over the block, while the other hand applies the necessary lubricants or additional pressure to assist the process. There are an infinite number of tool designs that can be forged in steel to assist in spinning a variety of shapes.

The products created by hand spinning cover a wide range: prototypes of beverage cans, mechanical parts for satellites and aircraft, components for semiconductor manufacturing equipment, large parabolic antennas, and so on—many products of all different sizes. The use of hand spinning has many manufacturing and economic benefits.

There are several advantages of automatic spinning, as well. For example, it removes the many uncertainties of operator skill and operator-to-operator variations, making spinning highly repeatable and accurate. After a CNC machine has been programmed (or ‘trained’), it can automatically execute the instructions, hydraulically applying predetermined forces for predetermined lengths of time on precise areas of the blank, creating fairly identical parts. Such machines can automatically shape the part, trim or otherwise finish the edges, and eject the finished part. These programs can also be transferred from machine tool to machine tool, stored for future processing, and easily updated and refined for future runs. The use of highly skilled metal spinners is no longer necessary to run these machine tools. However, an operator must still be knowledgeable about the intricacies of metal spinning, as well as the control software required to run the part.

An ideal machine shop has both – hand spinning as well as CNC spinning capabilities. Manufacturers choosing to work in metal spinning can tap into the high production capabilities of an automated shop floor, but they may also require manual spinning to create more intricate architectural and decorative products. Combining both of these techniques allows for the mass production of the bulk of a product line through CNC automation, while finishing it up with hand spinning, to create a product that is hand-crafted.  Additionally, shorter run productions may be more cost-effective when completed with hand spinning, removing the time it takes to set up and program a CNC machine.

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Tags: metal fabricating, Metal Spinning, Custom Metal Spinning, manufacturing, Hand Spinning, CNC Spinning

Safety Under Pressure: Pressure Vessel Shape Matters

Posted by Samuel Ibrahim, Jr. on Fri, Jan 10, 2014

pressure vesselThe American Society of Mechanical Engineers (ASME) first published the Boiler & Pressure Code (BPVC) in 1915 in response to the need for safety measures in the production and use of boilers and pressure vessels. In the early 1900s, boilers and pressure vessels – closed containers designed to hold gases or liquids at a pressure substantially different from the ambient pressure – were new innovations. These innovations promoted and advanced industrial activity in the U.S., specifically for companies that utilized machines for long-range transportation and heavy lifting.

Safety, however, was an issue. Accidents and fatal disasters were caused by cheap production practices in the early 1900s, careless operations, and temperamental machinery. Because of these issues, the ASME’s BPVC was born and it has played a vital role in manufacturing and industry for almost a century.

Today, the BPVC has been adopted in some form by all 50 states in the U.S. and all provinces of Canada. Additionally, translations and copies of the code are used around the world, promoting pressure vessel safety on an international level. An article posted on the ASME website addresses the importance of pressure vessel safety: “Going by its definition, it is actually very important as the vessel, which comes in the shape of a closed container, is designed to hold gases or liquids at a pressure substantially different from the ambient pressure. If it doesn't, the consequences can be fatal.”

Pressure vessels come in all shapes and sizes, each of which can affect the strength andvarious pressure vessels function of the vessel. Common pressure vessel shapes include sections of spheres, cylinders, and cones, with the most common design being a cylinder with end caps called “heads.” The heads of most pressure vessels are often shaped liked dishes, a round/circular design. According to the previously cited ASME article, “More complicated shapes have been more difficult to analyze for safe operation and are usually far more difficult to construct.” Shape can also affect the strength of a pressure vessel, with spherical pressure vessels having twice the strength of cylindrical pressure vessels.

While the shape of a pressure vessel may present production and safety challenges for some manufacturers, that’s not the case for Helander Metal Spinning Company. Helander manufactures pressure vessels of varying shapes and sizes, fabricating seamless custom pressure vessel shells through a special hot spinning process that creates vessels made from stainless steel, mild steel, or aluminum. The pressure vessels can be manufactured with or without bottlenecks depending on a customer’s specifications, and all pressure vessels manufactured by Helander meet ASME safety standards. For more information about custom pressure vessels, specifications, and manufacturing capabilities, visit Helander’s website.

 

 

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Tags: metal fabricating, metal forming, Custom Metal Spinning, Custom Fabrication, Custom Pressure Vessels, ASME Safety Standards

The Case for Metal Spinning and Metal Hydroforming

Posted by Samuel Ibrahim, Jr. on Thu, Oct 10, 2013

Metal Spinning is a process by which a disc or tube of ductile metal is rotated on a spindle and formed into an axially symmetric part. Through the use of heavy forces and high speeds, the metal will deform and “flow” to form the desired shape around a mandrel, a kind of mold that is shaped to the interior geometry of the planned part. This process allows metal to deform evenly, without any wrinkling or warping, to create a smooth, even, and seamless surface. The processes’ heavy forces also realign and strengthen the grain structure, significantly increasing the tensile properties and fatigue resistance of the base material.

Metal Spinning offers a series of compelling benefits for prototype and specialty work. High precision tolerances are easily attained on a wide variety of metal materials and designs. Mandrels are easily manufactured using traditional lathe and mill work, and considering that they are not subjected to excessive force in normal use, may be made of nonmetal materials. CNC control, hydraulic assistance, heat for hot working, and toolholders can all be incorporated into the metal spinning process. Overall, Metal Spinning permits an unparalleled level of flexibility, speed, and efficiency without sacrificing the precision and accuracy delivered by traditional processes.

For designs that are not conducive to spinning operations, Metal Hydroforming provides similar benefits and efficiency gains, effectively replacing work performed by machining or dies. The sheet hydroforming technique replaces one of the rigid dies used in conventional stamping with highly pressurized hydraulic fluid, contained by a urethane diaphragm, to force the sheet metal into a one-sided die cavity. Since the diaphragm, which is essentially acting as the female die, has no distinct shape, its dynamics allow it to take on the shape of any conceivable geometry. Complicated shapes with concavities are now possible in a single press cycle, reducing the amount of follow-up work and required forming operations. Produced to net shape, a single hydroformed component can often replace multiple parts, resulting in assemblies with fewer parts, higher strength, and less cost.

Metal Hydroforming brings many advantages over the typical die press processes that it replaces, especially in the context of prototype and specialty work. New part designs only require replacement of the lower die, which is usually made of cheaper cast iron and not expensive tool steel. During pressure application, friction and stress on the sheetmetal is significantly diminished, resulting in more consistent stressing and increased material drawability. Supplemental finishing operations are not necessary as the material is not marred as it is in standard die operations. Simplicity, efficiency, and service life are all upgraded significantly with Metal Hydroforming.

With the combination of these two processes, a new, and far better, system for prototype and specialty work is realized. Metal Spinning and Metal Hydroforming provide a definite pathway for one-off productions, design formulation, scratchwork, and design qualification, and simultaneously provide a full replacement for expensive, time-consuming traditional methods. Furthermore, both processes may work with just about any cold formed metal, and are easily reconfigured for high production work without any sacrifice in quality. Once the prototype becomes the new product, Metal Spinning and Metal Hydroforming are flexible enough to become the manufacturing system for it.

Helander Metal Spinning is an experienced provider of those two services, able to add Metal Spinning and Metal Hydroforming capability to your production paradigm. Helander’s engineers, manufacturing technologists, and material specialists can provide in-depth analysis of component design, advise you on the feasibility and practicality of using metal spinning or hydroforming to form your component part, and can completely manage the production thereof within their state-of-the-art manufacturing facility. Contact us today to let us help you decide what’s best for your bottom line.

 

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Tags: metal fabricating, metal forming, Metal Spinning, hydroforming, Custom Metal Spinning, Metal Stamping

The Advantages of Metal Spinning

Posted by Samuel Ibrahim, Jr. on Tue, Sep 10, 2013

 

  Custom Pressure Vessel Shells   Helander Metal Spinning  Lombard, IL
  5.60” diameter X 12” to 32” long X 0.250” thickness X 6061-0 aluminum vessel.

Metal spinning is a unique process that can be used to form complex shapes from aluminum steel, stainless steel, high-strength and high-temperature alloys, and many other metals. Metal spinning is a metalworking process by which a disc or tube of metal is rotated at high speed and formed into an axially symmetric part and is normally performed by hand or with CNC technology. Spinning metal is an inexpensive alternative to the stamping process, with a quicker processing time. Production prototypes can not only be designed on the fly but most changes to a design can be accomplished without added expense to the customer.

Because spun parts have no seams, they can withstand higher internal or external pressures. This is due to grain structure of the metal spun part, which is realigned, improving the metallurgy, as well as improving the tensile strength of the material. This also allows for a lighter gauge material to be used, saving on material cost. Some examples are scuba tanks, CO2 cartridges, and oxyacetylene tanks. Other products that can be produced by metal spinning range from small hardware items made in large quantities, such as metal tumblers and automotive components, to large components for aerospace applications. Metal spinning can be used to cost-effectively produce single or a small number of parts out of expensive materials, such as platinum, or large quantities of components of low-cost materials, such as aluminum. Cost savings are further enhanced from the inherent smooth finish that spinning produces, often eliminating the need for additional machining. Other advantages are very low tooling compared to stamping, as well as very short setup and changeover times. The process is also eco-friendly with less waste being produced.

Metal spinning provides an economical solution for products that require structural integrity. A wide range of shapes can be produced with relatively simple tooling. Here’s a video demonstrating the process at work.

 

Description

Carried out by the application of an even, force applied to metal uniformly by rotating the metal at very high rpm’s.  Metal is deformed evenly in the metal spinning process without any wrinkling or warping.

Equipment Used

Can be performed by hand or by a CNC lathe.

Material Used

Virtually any ductile metal may be formed; ranging  from aluminum or stainless steel to high-strength, high-temperature alloys.

Restrictions

Diameter and depth of formed parts are limited only by the size of the equipment available.

Advantages

  • Several operations can be performed in one set-up
  • Changes in part design can often be made through changes in tooling, particularly if the change is a reduction in size
  • Smaller amount of waste products produced
  • Produces products without seams (part can withstand higher internal or external pressure exerted on it)
  • Assures a higher degree of reliability on parts that have a structural function
  • Avoids warping
  • Lead times are usually shorter compared to other tooling methods
  • Low-cost tooling
  • Depending on volume, tolerance, and capability of the part, tooling material options include tool steel, engineered plastics, and wood
  • Improves the metallurgy by realigning the grain structure of the metal.  Tensile strength is improved, allowing lighter gauge material to be used in the same application.

Industry for Use

All industry

Volume

Typical production runs of 1,000 pieces or less
For prototype and limited production quantities
Typical volume range  50,000 units per year

Standards Met

Customer specifications

 

//www.youtube.com/embed/hTyAUWlM9LY?rel=0

“Spinning,” Author(s): B.P. Bewlay, General Electric Global Research, D.U. Furrer, Ladish Company

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Tags: metal fabricating, metal forming, Metal Spinning, manufacturing, welding, stainless steel, aluminum

Metal Spinning at Fabtech: Developments Circulating at the Show

Posted by Samuel Ibrahim, Jr. on Thu, Dec 08, 2011

Metal forming and fabricating are our business here at Helander, so we’re lucky to be so close to the annual Fabtech conference held just up the road in Chicago, this year at McCormick Place. This year’s show, held from November 12th through November 14th, proved just as educational, interesting, and, most of all, fun as in years past. Walking around, taking in all the different booths and displays, it’s quickly apparent that a good 50% or more of the exhibits focus on metalforming – certainly of interest to us, but not quite up our alley, not quite the art of metal spinning.

Fortunately, at a huge show like Fabtech, you can’t go too far without coming across something that does catch your eye. In our case, we were on the lookout for exhibits about the convergence of metal spinning and hydroforming. The interfaces for this technology are changing and evolving quickly, allowing for some of the most precise and repeatable functions available in manufacturing. Hand-in-hand with this type of accuracy is an improved ability to troubleshoot problems: with finer detail and more thorough recording of processes, production issues can be isolated and rectified much more quickly than previously.

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Tags: metal fabricating, metal forming, Fabtech